The Clinical Resources Core will identify and characterize human subjects for participation in the program project. We have several large on-going clinical studies for the ascertainment of pre-diabetic individuals, as well as a large specialty clinic for the recruitment of new-onset diabetics and their family members. The purpose of this core is to direct some of the efforts of these ongoing clinical studies for the specific recruitment of individuals appropriate to this study. By building on the strengths of pre-existing clinical registries and assay development we are able to accomplish a very efficient recruitment of suitable individuals at rather low cost, and propose this as a core function jointly directed by Dr. David McCulloch at Virginia Mason Medical Center and Dr. Bill Hagopian at the University of Washington School of Medicine. We conservatively estimate identifying at least 12 pre-diabetic individuals who will progress to clinical IDDM in the course of this project and at least an equal number of clinical non-progressors who carry the pre-diabetic markers. The third set of individuals to be studied will be an age- and sex-matched control group who carry the IDDM- associated DQ alleles, but are otherwise negative for pre-diabetic phenotypes.